05-11-2012, 04:37 PM
Adaptive cruise control system(ACC)
Adaptive cruise control.ppt (Size: 700.85 KB / Downloads: 43)
Common Terms in ACC
Response time of the driver (t): time needed by the driver to response safely to any unwanted disturbances (approximately about 2-3 sec)
Safe distance: the distance between vehicle equipped with ACC to the leading vehicle in front where the driver is still able to response safely in case of emergency brake happened to the vehicle in front
FUNCTION OF ACC SYSTEM
Preset and maintain the car speed
Measure the distance to the preceding car and the relative speed
Adjust the car speed accordingly
Maximum deceleration = 3.5m/s^2
TYPES OF ACC SYSTEM
Radar-Based System
– Three overlapping radar-beams (76-77kHz)
-- Detects moving object up to 120 m
– work in poor weather conditions
Laser-Based System (lidar)
– less expensive and easier to package
– light beams are narrower than water droplet and snowflakes
USE OF ACC SYSTEM
First laser-based system – Toyota’s Progress, a compact luxury sedan, in 1998
First radar-based system – Nissan’s Cima 41LV-2, a luxury sedan
First American ACC model – Lexus’ LS 430, in 2000
PRONS AND CONS OF ACC
PRONS-
1.Speed is adjustable and controlled.
2.Time gap and distance is being maintained to avoid any collision between two vehciles.
3.Easily sensed and adapt the speed accordingly to traffic environment.
Cons-
1.High in cost and assembles only in luxurious car. 2.Laser system failed in rainfall prone area due to shock circuit in system .